Recently, the semiconductor industry has developed an ultra-fine technique having a pattern of several to several tens of nanometers in size. Such ultrafine technique essentially needs effective lithographic techniques.
The typical lithographic technique includes providing a material layer on a semiconductor substrate; coating a photoresist layer thereon; exposing and developing the same to provide a photoresist pattern; and etching the material layer using the photoresist pattern as a mask.
Nowadays, when small-sizing the pattern to be formed, it is difficult to provide a fine pattern having an excellent profile by only the above-mentioned typical lithographic technique. Accordingly, a layer, called a hardmask layer or a resist underlayer, may be formed between the material layer to be etched and the photoresist layer to provide a fine pattern.
On the other hand, it has been recently suggested to form a resist underlayer by a spin-on coating method instead of chemical vapor deposition. The resist underlayer plays the role of an intermediate layer for transferring the fine pattern of photoresist to the material layer through a selective etching process. Accordingly, the resist underlayer is required to have chemical resistance, heat resistance and etch resistance and the like during the multiple etching processes.